Function emitGoRequiredFieldDiscriminatedUnion

scripts/codegen/go.ts:1986–2084

(
    typeName: string,
    discriminator: GoRequiredFieldDiscriminatorInfo,
    ctx: GoCodegenCtx,
    description?: string,
    experimental = false
)

}

function emitGoRequiredFieldDiscriminatedUnion(
    typeName: string,
    discriminator: GoRequiredFieldDiscriminatorInfo,
    ctx: GoCodegenCtx,
    description?: string,
    experimental = false
): void {
    if (ctx.generatedNames.has(typeName)) return;
    ctx.generatedNames.add(typeName);

    const unionVariants = [...discriminator.variants].sort((left, right) => compareGoTypeNames(left.typeName, right.typeName));
    const unmarshalFuncName = goUnexportedFunctionName("unmarshal", typeName);
    const rawDataName = `Raw${typeName}${ctx.discriminatedUnionRawVariantSuffix ?? "Data"}`;
    const markerName = toGoUnexportedIdentifier(typeName);
    ctx.discriminatedUnions.set(typeName, { typeName, unmarshalFuncName });

    const lines: string[] = [];
    if (description) {
        pushGoCommentForContext(lines, description, ctx);
    }
    if (experimental) {
        pushGoExperimentalTypeComment(lines, typeName, ctx);
    }
    lines.push(`type ${typeName} interface {`);
    lines.push(`\t${markerName}()`);
    lines.push(`}`);
    lines.push(``);

    for (const variant of unionVariants) {
        pushGoEncodingBlock(goVariantMatchFunctionLines(variant, unionVariants, "", ctx), ctx);
    }

    const unmarshalLines: string[] = [];
    unmarshalLines.push(`func ${unmarshalFuncName}(data []byte) (${typeName}, error) {`);
    unmarshalLines.push(`\tif string(data) == "null" {`);
    unmarshalLines.push(`\t\treturn nil, nil`);
    unmarshalLines.push(`\t}`);
    for (const variant of unionVariants) {
        unmarshalLines.push(`\tif ${goVariantMatchFuncName(variant.typeName)}(data) {`);
        unmarshalLines.push(`\t\tvar d ${variant.typeName}`);
        unmarshalLines.push(`\t\tif err := json.Unmarshal(data, &d); err != nil {`);
        unmarshalLines.push(`\t\t\treturn nil, err`);
        unmarshalLines.push(`\t\t}`);
        unmarshalLines.push(`\t\treturn &d, nil`);
        unmarshalLines.push(`\t}`);
    }
    unmarshalLines.push(`\treturn &${rawDataName}{Raw: data}, nil`);
    unmarshalLines.push(`}`);
    pushGoEncodingBlock(unmarshalLines, ctx);

    lines.push(`type ${rawDataName} struct {`);
    lines.push(`\tRaw json.RawMessage`);
    lines.push(`}`);
    lines.push(``);
    lines.push(`func (${rawDataName}) ${markerName}() {}`);
    pushGoEncodingBlock([
        `func (r ${rawDataName}) MarshalJSON() ([]byte, error) {`,
        `\tif r.Raw != nil {`,